Some vehicles include an operational mode in which a computing system is used to navigate and/or maneuver the vehicle along a travel route with minimal or no input from a human driver. Such vehicles include sensors that are configured to detect information about the surrounding environment, including the presence of objects in the environment. The computing systems are configured to process the detected information to determine how to navigate and/or maneuver the vehicle through the surrounding environment. In some instances, the vehicle may encounter objects that are not expected in the surrounding environment.